In industrial transmission systems,the reliability of shaft-hub connections directly determines the service life and stability of equipment.As a core industrial equipment for conveying high-viscosity media,the selection of shaft-hubb connections for rotary lobe pumps is a key link affecting the performance of the whole machine.Key,spline,keyless and pin connections,as the four most commonly used shaft-hub connection solutions,each have unmatched advantages and clear application boundaries.

-Bonve Pumps Cam Type Twin Rotor Pump-

Key connection is the most widely used circumferential fixing method in the industrial field.Among them,flat keys have become the first choice for most general transmission scenarios due to their convenient assembly and disassembly and good neutrality.Flat keys transmit torque through extrusion on both side surfaces,and a certain gap is reserved between the upper surface of the key and the bottom of the hub groove during installation,which can meet the basic transmission requirements of ordinary reducers and pulleys.However,key connection requires machining keyways on the shaft body,which will cause significant stress concentration and greatly reduce the fatigue strength of the shaft.For tapered shaft connections,woodruff keys can be used,which can automatically adapt to the slope of the keyway but cause more severe weakening of the shaft body;if parts need to move along the axial direction,guide flat keys or feather keys should be adopted.

Spline is essentially an integrated structure of multiple key teeth,and its bearing capacity and centering accuracy are far superior to single key connections.The characteristic of simultaneous force bearing of multiple teeth significantly reduces the extrusion stress per unit area.Moreover,splines have shallow tooth roots and lower sensitivity to stress concentration,so the strength weakening to the shaft body is actually less than that of single keys.Splines are mainly divided into rectangular and involute types.Rectangular splines adopt minor diameter centering with mature technology and stable accuracy;involute splines rely on tooth profile centering and have automatic centering function under load,making them an ideal choice for high-speed and heavy-duty working conditions.However,their processing requires special hobbing or broaching equipment,and the initial manufacturing cost is relatively high.

The typical representative of keyless connection is expansion sleeve connection.It transmits torque through the friction force of the contact surfaces and does not require slotting on the shaft body at all,which eliminates the hidden danger of stress concentration at the root.By tightening high-strength bolts to generate radial pressure,a tight interference fit is formed between the expansion sleeve,the shaft and the hub.This connection supports precise circumferential phase adjustment,and the shaft diameter size is not limited by standard keyways,making it particularly suitable for servo transmission systems with frequent disassembly or high-frequency forward and reverse rotation.Although the procurement cost is higher than that of standard keys,it can effectively extend the service life of the shaft and reduce long-term maintenance costs.

Pin connection has the simplest structure and mainly includes three types:cylindrical pins,taper pins and split pins.In shaft-hub connections,pins usually do not bear the main transmission load and are mainly used for precise positioning of parts or transmitting extremely small torque.Its most unique value is that it can be used as a safety pin.When the system load exceeds the preset threshold,the pin will undergo shear fracture first,thereby protecting valuable components such as motors and gears from damage.This overload protection feature is irreplaceable by other connection methods.

The four connection methods have their own advantages and disadvantages,which should be considered in combination with actual working conditions.For rotary lobe pumps,flat key connections can be selected to control costs under conventional conveying conditions,spline connections can be used for heavy-duty and high-precision requirements,keyless connections are more suitable for frequent start-stop and forward-reverse rotation conditions,and pin connections can be used in the safety protection link.

Bonve pump always adheres to the philosophy of "Wholeheartedly Making Good Rotor Pumps," committed to providing global customers with customized conveying and mixing solutions. If you have technical inquiries, selection needs, case references, or other cooperation intentions related to Bonve rotor pumps, please feel free to contact us.  

Service Hotline: 0574-87588986 13586591794  

Official Website: www.bvpumps.com  

Business Email: market@bonvepumps.com  

We look forward to working with you to drive efficiency and innovation in industrial fluid transmission with precision technology.